Page 105 - AJWEP-22-6

Adsorption desulfurization

Figure 12. The adsorption mechanism diagram of TP on the RuY adsorbent.
Abbreviations: NH₄Y: Ammonium-form Y-zeolite; Ru: Ruthenium; RuY: Ruthenium-modified Y-zeolite.

Table 2. Langmuir and Freundlich isotherm radius of the Mⁿ⁺ in the MY adsorbents. XPS analysis
parameters for TP adsorption on RuY-1/2 adsorbent confirmed the oxidation states of the metal ions in the
3+
3+
4+
5+
4+
Model K q (mg/g) n K R 2 MY-1 adsorbents as Bi , Sb , Sb , Ru , and Zr .
L m F Their ionic radii are as follows: Bi ⁺: 103 pm; Zr ⁺: 72
3
4
Langmuir 1.52 0.488 - - 0.975 4 5
Freundlich - - 7.704 0.412 0.687 pm; Ru³⁺: 68 pm; Ru ⁺: 62 pm; and Sb ⁺: 60 pm. Smaller
ionic radius and higher charge enhance polarization
Abbreviations: K F : Freundlich constant; K L : Langmuir constant; energy, leading to stronger S–M bond formation. Among
n: Freundlich heterogeneity factor; q m : Maximum adsorption
capacity; R²: Coefficient of determination; TP: Thiophene. the tested adsorbents, RuY-1 showed the highest sulfur
removal, confirming that Ru ⁺ forms stronger S–M
4
3
4
where C is the remaining concentration of TP at σ bonds than Zr ⁺ or Bi ⁺. This suggests that smaller-
e
equilibrium (mg/L), q is the amount of TP adsorbed radius and higher-valent metal ions promote stronger
e
at equilibrium (mg/g), q is the theoretical maximum interactions with thiophene molecules, enhancing
m
adsorption capacity (mg/g), K is the Langmuir selective adsorption (Figure 12).
L
isotherm constant (L/mg) reflecting the strength of
adsorption, K is the Freundlich isotherm constant 4. Conclusion
F
(L/mg) related to multilayer adsorption capacity, and
n is the Freundlich empirical constant related to the Metal ion modified MY-1 zeolite adsorbents exhibit
intensity of adsorption. selective adsorption for TP from low-sulfur concentration
model gasoline. The solid-state reaction method proves
The adsorption isotherm of TP on RuY-1/2 adsorbent effective for preparing these MY-1 adsorbents. Among
at 80°C is shown in Figure 11. The equilibrium them, the RuY-1/2 adsorbent, modified with Ru ⁺ cluster
4
parameters of the model are summarized in Table 2. The ion, showed the highest sulfur removal efficiency. The
calculated n is 7.074, and 1/n ranges from 0.1 to 0.5, selectivity of MY-type adsorbents for TP depends on
suggesting that the adsorption process can easily occur. key properties of the incorporated metal ions: smaller
The adsorption data fit the Langmuir model better ionic radius, higher charge, and greater concentration of
than the Freundlich model, with a higher correlation Lewis acid sites.
coefficient (R = 0.9758) compared to the Freundlich
2
model (R = 0.6873). This indicates that TP adsorption on Acknowledgments
2
RuY-1/2 proceeds primarily via monolayer adsorption
onto a homogeneous surface. None.
Based on the direct S–M interaction mechanism for
thiophene adsorption, the σ-bond interaction between Funding
sulfur and metal cations (e.g., Ce⁴⁺ in CeY, La³⁺ in LaY)
is stronger than the π-complexation interaction (e.g., Cu⁺ This study was supported by the Basic Scientific
in CuY, Ag⁺ in AgY), offering better selectivity and Research Project of the Higher Education Department
efficiency for ultra-deep desulfurization. 14,29 The S–M of Liaoning Province (LJ212410142153), Liaoning
σ bond strength depends on the valence state and ionic Province Science and Technology Plan Joint Plan

Volume 22 Issue 6 (2025) 99 doi: 10.36922/AJWEP025250204